1. Field of the Invention
The present invention relates to a writable/rewritable optical recording medium, and more particularly, to an optical recording medium such as a digital versatile disc rewritable (DVD-RW) on which basic recording units are seamlessly connected, and a method of processing a defective area occurring on the recording medium.
2. Description of the Related Art
Conventionally, the management of defects on a writable/rewritable disc is performed only for DVD-random access memory (DVD-RAM). For a defect (primary defect) occurring while a disc is being initialized, a method of slipping replacement is used to slip the defective area without allocating a logical sector number. For a defect (secondary defect) occurring while a disc is being used, a linear replacement technique is used to replace an error correction code (ECC) block including the defective area with a normal ECC block within a spare area.
A DVD-RW, on the other hand, has a recording management data (RMD) area for recording a list of detected defective areas, but a detailed method of detecting defective areas (for example, a certification method) is not defined by any standard. Accordingly, such a method of processing defective areas is needed.
Unlike a DVD-RAM in which basic recording units are discriminated from the others by physical identifiers (PIDs) or a buffer field (a spare area assigned for overcoming the limit caused by accurate control of the spindle motor), in a DVD-RW, basic recording units are seamlessly recorded without discrimination, so it is necessary to clarify the start point of each basic recording unit. The basic recording unit of a DVD-RAM may be a sector, and the basic recording unit of a DVD-RW may be an ECC block.
The three recording modes of a DVD-RW disc are: disc at once recording mode, overwriting recording mode and incremental recording mode.
When recording in any of these three modes is resumed after having been interrupted, DVD recordables (DVD-Rs) and DVD-RWs, which have the same physical format, employ a linking scheme having 5 bytes of margin for a next recording start point. However, a user data area may be lost when using the linking scheme.